In a modern drilling rig, much of the associated equipment is driven electrically. For some drilling rigs, generators are used to supply electricity to the drilling rig. In general, generators are most efficient when producing power within a certain range of power output. During drilling operations, electric loads may vary greatly depending on what is happening at the rig at any given time. Electrical equipment, including drawworks, mud pumps, top drives, rotary tables, etc. may consume large amounts of power when in use. Because each piece of equipment is used intermittently, the power drawn by the drilling rig may vary greatly at different times, at times going from very high to very low in short intervals. At other times, very little power is consumed by the drilling rig equipment. Additionally, a rapid decrease in electric load may cause a power spike which may cause the rig and generator to automatically shut down.